Existing and future wireless communication standards focus on improving spectral efficiency and data throughput. In terms of data throughput in particular, the developing wireless communication standards offer significantly improved performance as compared to earlier standards, such as GSM, GPRS, IS-95, and CDMA2000. For example, Release 7 of the Wideband Code Division Multiple Access (WCDMA) standards defines radio link peak data rates approaching or exceeding 28.8 Mbits/s. Future radio standards are expected to continue increasing peak data rates.
Achieving anything close to the defined peak data rates in actual practice requires the use of high-quality signal transmitters and receivers. For example, virtually all contemporary (and planned) wireless communication devices include channel estimation processing, wherein “channel estimates” are generated to account for the distortion caused by propagating an electromagnetic signal from the transmitter to the receiver. The quality of channel estimation at the receiver directly affects its ability to recover transmitted information from the received signal with acceptably low error rates.
Known efforts to improve channel estimation include the adoption of minimum mean square error estimation techniques. For example, the co-pending and commonly assigned U.S. patent application, as filed on 6 Nov. 2007 and assigned application Ser. No. 11/935,604, discloses a minimum mean square error (MMSE) channel estimation process that obtains the MMSE solution for medium channel coefficients as a function a medium coefficient correlation matrix, an impairment correlation matrix, and (measured) net channel responses.